MEDIUM SUPPLEMENTATION WITHL- ANDD-AMINO ACIDS RELATIVE TO GROWTH AND EFFICIENCY OF RHIZOBIUM MELILOTI

1966 ◽  
Vol 12 (2) ◽  
pp. 275-283 ◽  
Author(s):  
B. W. Strijdom ◽  
O. N. Allen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rhizobium Meliloti ◽  
Basal Medium ◽  
Nitrogen Fixing ◽  
Mineral Salts ◽  
Acid Media ◽  
Maximum Loss ◽  
Serial Cultivation ◽  
Medium Supplementation

Five strains of Rhizobium meliloti serially cultivated on a basal yeast water mannitol mineral salts medium supplemented with increments of nine amino acids, respectively, produced ellipsoidal, bacteroidal, and elongated cell forms. Colonies produced on media containing D-amino acids and glycine were smaller and less opalescent than were those on the basal medium. Growth of two strains on media supplemented with the L-isomers of alanine, histidine, and phenylalanine, respectively, exceeded that in media to which the D-isomers of these amino acids were added. Growth was negative or sparse in the basal medium supplemented with 0.075% L-cysteine. Serial cultivation in media containing increments of D-cysteine, D-alanine, D-phenylalanine, and glycine produced the maximum loss in nitrogen-fixing ability; L-alanine and L-histidine were the least deleterious. Four strains became ineffective after serial cultivation on at least two of the nine amino acid media. The infective and nitrogen-fixing properties of an ineffective strain were unchanged after cultivation in amino acid supplemented media.

INHIBITION OF GROWTH OF PSEUDOMONAS DENITRIFICANS BY AMINO ACIDS

1966 ◽  
Vol 12 (6) ◽  
pp. 1095-1098 ◽  
Author(s):  
Horace J. Daniels
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Basal Medium ◽  
Ammonium Phosphate ◽  
Complete Medium ◽  
Mineral Salts ◽  
Culture Studies ◽  
Pseudomonas Denitrificans ◽  
Inhibition Of Growth ◽  
Amino Acid Mixtures

A large number of amino acids failed to support growth of Pseudomonas denitrificans in a basal medium composed of glucose, ammonium phosphate, and other mineral salts. Inability of an amino acid to support growth correlated well with its inhibitory action in a complete medium made up by adding L-glutamic acid to the basal medium. D-Amino acids were more toxic than the corresponding L-forms, and neutral amino acids were more toxic than acidic amino acids. Basic amino acids which were least toxic supported the best growth. The danger of the indiscriminate use of amino acid mixtures for culture studies is discussed.

THE APPLICATION OF A NUTRITIONAL GROUPING METHOD TO SOIL FUNGI

1955 ◽  
Vol 33 (3) ◽  
pp. 281-288 ◽  
Author(s):  
R. G. Atkinson ◽  
J. B. Robinson
Keyword(s):  
Amino Acids ◽  
Growth Factors ◽  
Yeast Extract ◽  
Soil Fungi ◽  
Basal Medium ◽  
Maximum Growth ◽  
Potassium Nitrate ◽  
Soil Extract ◽  
Mineral Salts ◽  
Soil Extracts

In tests with seven different liquid media in which the common nitrogen source was potassium nitrate and the carbohydrate substrate was glucose, at a concentration of only 0.1%, most of the 1914 soil fungi isolated fell into one of three nutritional groups requiring, respectively, for maximum growth amino acids, amino acids plus growth factors, or yeast extract. Relatively few isolates required growth factors alone or a combination of yeast and soil extracts. Most of the isolates grew poorly in the basal medium containing only mineral salts, and glucose, with or without soil extract. Although fungi requiring yeast extract were much less frequently isolated from soil on, rather than remote from, tubers grown in a soybean green-manured plot, isolates requiring amino acids, or yeast plus soil extracts, were correspondingly increased on immature and mature tubers, respectively. In a second plot, however, not specially treated, no differences were observed in the nutritional spectra of fungi isolated from the two kinds of soil environment.

Ultrastructure of a caffeine-resistant mutant of Aspergillus parasiticus during aflatoxin production

1987 ◽  
Vol 45 ◽  
pp. 978-979
Author(s):  
S. B. Jones ◽  
T. O. Dobson ◽  
H. G. Stahl ◽  
R. L. Buchanan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspergillus Parasiticus ◽  
Resistant Mutant ◽  
Aflatoxin Production ◽  
Mineral Salts ◽  
Ultrastructure Study ◽  
Fungal Pellets ◽  
Aflatoxin Accumulation

Caffeine (1,3,7-trimethylxanthine) inhibits growth and aflatoxin synthesis in A. parasiticus. A caffeine-resistant mutant (BCR1) of A. parasiticus NRRL 2999 was isolated in which sporulation and aflatoxin production occurred only in the presence of caffeine. Further, when cultured in glucose-mineral salts (GMS), BCR1 required amino acids in addition to caffeine in order to produce aflatoxin. A system for ultrastructure study was thus available in which aflatoxin synthesis was controlled by supplementation with amino acids. Experiments were conducted to identify morphology that could be correlated with aflatoxin production in the mutant.Cultures were conidia-initiated in GMS at 28C with agitation, with 6% peptone as amino acid source. Caffeine at 4 mg/ml permitted full growth and stimulated maximal aflatoxin accumulation. Fungal pellets were retrieved at 4 days and portions of the periphery were fixed in 3% glutaraldehyde in 80 mM Na-cacodylate, pH 7.0, for 3 hr.

The Quantitative Utilization of Amino Acids and Glucose and Contact Inhibition of Growth in Cultures of the Human Diploid Cell, WI-38

1970 ◽  
Vol 6 (3) ◽  
pp. 739-749
Author(s):  
J. B. GRIFFITHS
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Basal Medium ◽  
Diploid Cell ◽  
Contact Inhibition ◽  
Growth Media ◽  
Acid Uptake ◽  
Human Diploid Cell ◽  
Inhibition Of Growth ◽  
Diploid Cells

There are many reports in the literature showing that contact inhibition of growth is affected by the culture medium. A quantitative study of amino acid and glucose uptake by the human diploid cell line, WI-38 was carried out to determine more precisely what effect nutritional factors have on contact inhibition of growth. Eagle's minimal essential medium (MEM) was found to support higher cell yields than Eagle's basal medium (BME) and for growth to continue beyond 96 h a medium change was essential. However, analysis of the used growth media showed that neither amino acids nor glucose were fully depleted after 96 h. The rate of glucose utilization was in the range 65-100µg/mg dry wt./h and this agreed very closely with the results of other authors. The pattern of amino acid uptake also closely resembled that for other cell lines except that the utilization of cystine was higher. The nutritional requirements were further studied as the results from the medium analyses failed to explain the growth-promoting activity of MEM. Daily medium changes greatly increased cell yields even though the medium nutrients were not exhausted. This effect was dependent upon fresh medium being used and the only medium component found to be of importance was the amino acid complement. These results are discussed in relation to the low saturation density of diploid cells in culture and a possible explanation is proposed in terms of differences in the cell membrane between normal and altered cells.

THE UTILIZATION OF PURINES, PYRIMIDINES, AND INORGANIC NITROGENOUS COMPOUNDS BY EFFECTIVE AND INEFFECTIVE STRAINS OF RHIZOBIUM MELILOTI

1955 ◽  
Vol 1 (8) ◽  
pp. 668-674 ◽  
Author(s):  
D. C. Jordan ◽  
C. L. San Clemente
Keyword(s):  
Amino Acids ◽  
Carboxylic Acids ◽  
Ammonium Chloride ◽  
Rhizobium Meliloti ◽  
Synthetic Medium ◽  
Nitrogen Sources ◽  
Sole Source ◽  
Acid Media ◽  
Nitrogenous Compounds ◽  
Growth Initiation

Ammonium chloride was not utilized by three strains of Rhizobium meliloti as the sole source of nitrogen in a sucrose medium, unless either amino or certain non-nitrogenous carboxylic acids were also present. This was also essentially true for the utilization of nitrate, nitrite, purines, and pyrimidines, all of which are potentially able to form ammonia. These results may be interpreted on the assumption that washed cells of alfalfa – sweet clover rhizobia require, for growth initiation in a nitrogen-free medium, either preformed amino acids or compounds such as ammonia and certain carboxylic acids from which amino acids can be synthesized. Since α-ketoglutarate was extremely active in promoting growth in a medium containing ammonium chloride it was implied that the ammonia may be fixed by L-glutamic acid dehydrogenase activity, especially since this particular enzyme was located in these organisms. No aspartase activity could be demonstrated. The ineffective strain differed from the effective strains in that it was unable to use purines or pyrimidines as accessory nitrogen sources in amino acid media. This was a result of strain variation and it was not coupled with the state of ineffectiveness itself. A synthetic medium has been formulated for further growth studies on washed Rhizobium cells and for investigations on auxotrophic mutants of these bacteria.

Nutritional Factors Affecting Growth and Production of Antimicrobial Substances by Streptococcus lactis subsp. diacetylactis S1-67/C

1983 ◽  
Vol 46 (6) ◽  
pp. 514-517 ◽  
Author(s):  
N. S. REDDY ◽  
B. RANGANATHAN
Keyword(s):  
Amino Acids ◽  
Yeast Extract ◽  
Casein Hydrolysate ◽  
Basal Medium ◽  
Good Growth ◽  
Mineral Salts ◽  
Nutritional Factors ◽  
Maximum Production ◽  
Antimicrobial Substances ◽  
Streptococcus Lactis

The present study pertains to the effect of nutritional factors on the growth and production of antimicrobial substances (AS) by Streptococcus lactis subsp. diacetylactis S1-67/C. Among nine media tested, yeast extract dextrose broth supported good growth and maximum production of AS. Addition of beef extract and yeast extract at 1.0 and 0.6% levels, respectively, increased growth as well as production of AS. Of ten carbohydrates examined, maximum production of AS was achieved with 1% glucose followed by fructose, 4% molasses, lactose, sucrose, galactose, mannitol, maltose and 2% molasses. Xylose inhibited production of AS, although it stimulated growth of the organism. Peptone, tryptone and tryptose (each at the 1.5% level) significantly stimulated production of AS. Other nitrogen sources, including soytone, casein hydrolysate and proteose peptone, retarded production of inhibitory substances. Among the amino acids, L-leucine, DL-methionine and L-glutamic acid were most essential for growth and production of AS, whereas L-lysine, L-proline, DL-serine, DL-asparatic acid, L-arginine-HCl and DL-tryptophan were stimulatory. Other amino acids such as DL-ornithine, L-cysteine-HCl and DL-citrulline slightly stimulated AS production. In the presence of cynocobalmin, niacin, folic acid, calcium pantothenate and riboflavin, S. lactis subsp. diacetylactis S1-67/C produced maximum amounts of inhibitory substances. Omission of individual mineral salts from the basal medium did not affect production of AS by the organism.

Requirements for Growth of Single Human Cells

PEDIATRICS ◽  
1959 ◽  
Vol 23 (4) ◽  
pp. 709-709
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Basal Medium ◽  
Optimal Growth ◽  
Essential Amino Acids ◽  
Human Cells ◽  
Human Nutrition ◽  
Traditional Concept ◽  
Original Medium ◽  
Number Of Cells

The experiments reported in this paper may foreshadow a change in the traditional concept of so-called essential amino acids in human nutrition. It has been shown that a number of strains of single types of human cells may be propagated serially in a medium containing 13 "essential" amino acids along with other ingredients when a relatively large inoculum of cells is employed. In the present experiments it was learned that this medium did not permit successful propagation if relatively small inocula of cells were used, unless additional amino acids not included in the original medium, were added. The efficiency of the medium in promoting growth in the case of lighter inocula was restored when seven amino acids, not required for optimal growth with heavy inocula, were added to the basal medium. Serine was the most important of the seven non-essential amino acids that were not required in the medium to support optimal growth with heavy inocula. Thus the essentiality or non-essentiality of an amino acid may depend upon the capacity of the number of cells involved to meet the requirements for amino acids by biosynthesis within the cells, as may be determined by the population of cells and their rate of growth.

OBSERVATIONS ON THE EFFECT OF AMINO ACIDS ON THE GROWTH INITIATION OF RHIZOBIUM MELILOTI, WITH SPECIAL REFERENCE TO THE SYNTHESIS OF ALANINE FROM PYRUVATE AND AMMONIUM IONS

1957 ◽  
Vol 3 (6) ◽  
pp. 911-921
Author(s):  
D. C. Jordan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Substrate Concentration ◽  
Rhizobium Meliloti ◽  
Resting Cells ◽  
Alkaline Ph ◽  
Ammonium Ions ◽  
Low Carbohydrate ◽  
Amino Acid Histidine ◽  
Growth Initiation

Washed cells of Rhizobium meliloti were capable of forming pyruvate from glucose and, in addition, washed cells and sonic extracts possessed a reversible alanine dehydrogenase, capable of forming alanine from pyruvate and NH4+. This synthesis of alanine was optimum at an alkaline pH and at a substrate concentration of 0.025 M and was stimulated by diphosphopyridine nucleotide but not by triphosphopyridine nucleotide. Sonic extracts in the presence of NH4+ also formed glutamate from α-ketoglutarate and aspartate from fumarate. Nevertheless, washed cells did not initiate growth in a 0.25% carbohydrate medium, containing NH4Cl, unless amino acids were present. These requisite acids either could be supplied in the medium, or the cells could be forced to synthesize them by addition to the medium of increased levels of certain compounds, such as 0.9% glucose, from which NH4+-accepting compounds could be produced. If the stimulative effect of amino acids in low-carbohydrate media were a result of an increase in the accumulation of such NH4+-acceptors such an accumulation did not apparently result from increased carbohydrate oxidation or decreased "oxidative" assimilation, since NH4+ and α-dinitrophenol, which do not initiate growth, were more active, respectively, in these two latter aspects than the amino acid (histidine) tested. On the basis of several considerations it is hypothesized that the primary effect of the growth-initiating amino acid may be directed toward the synthesis of a labile protein, intimately connected with growth, which is destroyed in resting cells.

Influence of Carbohydrate Starvation and Arginine on Culturability and Amino Acid Utilization of Lactococcus lactis subsp. lactis

1999 ◽  
Vol 65 (2) ◽  
pp. 665-673 ◽  
Author(s):  
Mark R. Stuart ◽  
Lan Szu Chou ◽  
Bart C. Weimer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Lactococcus Lactis ◽  
Basal Medium ◽  
Logarithmic Phase ◽  
Phase Growth ◽  
Cell Numbers ◽  
Carbohydrate Starvation ◽  
Amino Acid Utilization ◽  
Carbohydrate Depletion

ABSTRACT Two strains of Lactococcus lactis subsp.lactis were used to determine the influence of lactose and arginine on viability and amino acid use during carbohydrate starvation. Lactose provided energy for logarithmic-phase growth, and amino acids such as arginine provided energy after carbohydrate exhaustion. Survival time, cell numbers, and ATP concentrations increased with the addition of arginine to the basal medium. By the onset of lactose exhaustion, the concentrations of glycine-valine and glutamate had decreased by as much as 67% in L. lactisML3, whereas the serine concentration increased by 97% during the same period. When no lactose was added, the concentrations of these amino acids remained constant. Similar trends were observed for L. lactis 11454. Without lactose or arginine, L. lactisML3 was nonculturable on agar but was viable after 2 days, as measured by fluorescent viability stains and intracellular ATP levels. However,L. lactis 11454 without lactose or arginine remained culturable for at least 14 days. These data suggest that lactococci become viable but nonculturable in response to carbohydrate depletion. Additionally, these data indicate that amino acids other than arginine facilitate the survival of L. lactis during carbohydrate starvation.

Molecular Basis for Differential Metabolic Responses to Monosulfuron in Three Nitrogen-Fixing Cyanobacteria

Weed Science ◽  
2009 ◽  
Vol 57 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Jianying Shen ◽  
Antonio DiTommaso ◽  
Mingquan Shen ◽  
Wei Lu ◽  
Zhengming Li
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Genomic Dna ◽  
Higher Plants ◽  
Algal Species ◽  
Acetolactate Synthase ◽  
Nitrogen Fixing ◽  
Anabaena Azollae ◽  
Branch Chain Amino

Nitrogen-fixing cyanobacteria are vital photosynthetic microorganisms that contribute to soil fertility by fixing atmospheric nitrogen and are also important for maintaining ecosystem stability. These microorganisms can be very sensitive to herbicides because they possess many characteristics of higher plants. Six days after the application of monosulfuron at 0.03 to 0.3 nmol L−1under laboratory conditions, growth of the nitrogen-fixing cyanobacteriaAnabaena flos-aquae,Anabaena azollae, andAnabaena azoticawas stimulated, but at higher concentrations (30 to 300 nmol L−1) protein synthesis was inhibited. The production of 16 amino acids inA. flos-aquaewas reduced from 7 to 69% with increasing monosulfuron concentration. Application of monosulfuron at 3 to 300 nmol L−1substantially inhibited in vitro acetolactate synthase (ALS) activity as indicated by 50% inhibition index values of 3.3, 65.2, and 101.3 nmol L−1forA. flos-aquae,A. azollae, andA. azotica, respectively. In contrast, extractable ALS activity was not affected in these algal species with monosulfuron treatments ranging from 0.03 to 300 nmol L1except inA. flos-aquaeat higher concentrations (30 to 300 nmol L−1). The most sensitive species to monosulfuron wasA. flos-aquae, followed byA. azollaeandA. azotica. Molecular analyses showed that the genomic DNA ofA. azollaeandA. azoticadiffered in only one amino acid. Results from photogenetic analyses revealed a high degree of homology between these algae. In contrast, the genomic DNA ofA. flos-aquaediffered from that ofA. azollaeandA. azoticain 44 and 45 amino acids, respectively. Our findings support the view that monosulfuron toxicity in these three nitrogen-fixing cyanobacteria is due to interference with protein metabolism via inhibition of branch-chain amino acid biosynthesis, and particularly ALS activity.

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